Indoor Air Quality (IAQ) is measure for the quality of air in interiors, the comfortable indoor environmental quality can make people feel fresh, work efficiency and good for the health. The CO2 concentration is the important factor of good indoor air quality. People breath in oxygen and breath out CO2, nowadays people often close the windows to avoid noise and enjoy the comfort living and working environment provided by air-conditioning systems, which results in the fact that the indoor concentration of CO2 is far higher than outdoor average. With the high CO2 concentration and non- proper ventilation, people will feel headaches, dull, drowsiness, lose of concentration and correspond to the high levels of dust, chemicals and bacteria in the air.

Dimmer function: When the light indoor become dark, the LED display will also become dark, then it can save power.
Dark mode means LED brightness is lower in order to save power,especially for application in night.
Bright mode means LED brightness is higher especially for application in day.NGC Function: When the switch of “NGC Function” is on, ZGkb301/ZGkb201p will enter into the Nature Gas Calibration mode.Teach Mode: this is only for factory function checking, default is OFF.SelfTest: This is for only factory testing, default is OFF.

CO2, RH, Temperature measure mode

When CO2 concentration is below 800ppm, the green LED bar display area will light.

When CO2 concentration is between 800ppm and 1200ppm, the green and yellow

LED bar display area will light.

When CO2 concentration exceeds 1200 ppm, the green, yellow and red LED bar

display area will light.

When CO2 concentration exceeds the CO2 measurement range (0-3,000ppm), the

CO2 display area will display with “Hi”. It will disappear when the CO2 concentration

returns to the measurement range.

When RH exceeds the RH measurement range 20%, the humidity display area will

display with “Lo”. It will disappear when the RH returns to the measurement range.

When RH exceeds the RH measurement range 90%, the humidity display area will .

display with “Hi”. It will disappear when the RH returns to the measurement range